Control system



April 1940- E. w. FIELDS 2,195,954

CONTROL SYSTEM Filed July '7. 1937 w u e35 20 llj 1 1 mwa m az ATTORNEYS was; Apr. 2, 1940 UNITED STATES PATENT OFFICE IOlaim.

The invention relates to an electric heating and ventilating system and more especially to an automatically operated electric heating and ventilating apparatus for closed motor vehicles.

The primary object of the invention is the provision of an apparatus of this character, wherein an electric heater and an electric fan are independently operative so that the interior of a closed type of motor vehicle can be heated during cold weather and ventilated during warm weather, the heater and the fan being automatically controlled under the influence of a thermostat so that when the vehicle becomes heated to a determined degree the heater circuit will be caused to automatically open and simultaneously the fan circuit, which during the operation of the heater is open, will be closed for the working of the latter and vice versa on the temperature within the vehicle dropping below a determined degree the fan circuit will be opened and the heater circuit closed, thereby enabling the heating and ventilating of a motor vehicle automatically for assuring comfort to the user of such vehicle during warm and cold weather.

Another object of the invention is the provision of an apparatus of this character, which is extremely simple in its construction, thoroughly reliable and eificient in operation, automatically acting, durable, and inexpensive to manufacture and install.

With these and other objects in view, the invention consists in the features of construction, combination and arrangement of parts as will be hereinafter more fully described, illustrated in the accompanying drawing, which discloses the preferred and modified forms of embodiment of the invention and pointed out in the claim hereunto appended.

In the accompanying drawing:

Figure 1 is a diagrammatic plan view of a preferred embodiment of the system or apparatus in accordance with the invention.

Figure 2 is a fragmentary plan view of a slight modification.

Similar reference characters indicate corresponding parts throughout the several views in the drawing.

Referring to the drawing in detail, the apparatus comprises a bellows type thermostat ll having connection with a rocking arm ll arranged between and operating alternately opposite plvotally supported switch closing levers I2 and II, respectively, the pivot therefor being indicated at ll while active upon the lever are coiled retractile springs II which urge the same to a rest position against stops II. These levers l2 and I2 function for closing alternately a pair of switches II, one being arranged in an electric heater circuit ll including therein an electric heater f9 and the other arranged in an electric fan circuit including therein an electric fan 2!.

The circuits l8 and 20 are in electrical connection with a storage battery 22 which is the electric power source of supply and also included in these circuits are hand operated switches 22 while included in the connections between the said circuits and the battery 22 is a main hand switch 24. Thus by the opening manually of the switch 24 the battery 22 will be cut ofl from the circuits I8 and 20, then by operating the switch 23 in either of the circuits I2 and 2| when the switch 24 has been closed will open or close either of said circuits l8 or 20.

Assuming that the circuit II having the heater ll therein is closed to the battery 22 and likewise the circuit 20 having the fan 2i is closed to the said battery but the switch II in the circuit 20 is open while the switch II in the circuit l8 has been automatically closed under the working of the thermostat ID the electric heater I! will be active for heating purposes. Now when the heat from this heater i9 exceeds a determined degree the thermostat Ill operates to allow the switch I! in the circuit It to open and simultaneously the switch II in the circuit 20 will be closed, the opening of the switch in the circuit l8 shuts oil the heater l9 and the closing of the switch II in the circuit 20 starts the fan 2i in its operation. When the temperature drops below a determined degree, the fan 2i automatically is stopped under the action of the thermostat Ill opening the switch I! in its circuit 20 and simultaneously the switch I! in the circuit It will become closed whereupon the heater l8 operates.

In Figure 2 of the drawing there is shown a slight modification wherein the levers 25 and 26, respectively, having arranged therebetween and operative thereon a bi-metal rod-like thermostat 21 which is effected by temperature changes for flexing or bending in the alternate working of the levers 25 and 26 corresponding to the alternate action of the levers i2 and I2 before described.

Arranged in the circuit ll having the heater l0 and in parallel with the circuit is an electric lamp 2! which, when the heater is on, illuminates showing the working of such heater.

What is claimed is:

In a structure of the kind described having a heating device and a circulating device, a changeover switch for selectively putting alternately either or both devices into service and involving normally opened alternately closeabie springy contacts disposed opposite each other. a pair of opposed swinging levers having insulated terminals active against the contacts for alternately operating the same, springs connected with the levers for holding the same in spread relation to each other, a rocking arm having a cross head swingable between the levers and alternately engageable therewith tor actuating the same. and a thermostatic device having connection with the said arm for movement thereof under tempera- I ture changes.

mm W. FIELDS. 

